Precious metals (typically platinum alloys containing 0-20 wt % rhodium) are widely used in glass melting tanks due to their combination of high-temperature properties such as strength, ductility, weldability, resistance to oxidation, and relative inertness when exposed to glass-forming melts.
Formation of precious metal sourced inclusions and the coloring effect of rhodium are of concern. Rhodium inclusions in glasses can be mitigated and potentially eliminated by controlling the partial pressure of hydrogen on the non-glass-contact surface of precious metals and by batching multivalent oxides in the glass composition, as reported. However, minimization of rhodium dissolution from precious metal alloys used in the glass melting process and the coloring effect of rhodium on glass or glass-ceramics has not been investigated.